Enzymatic method of making pectic preparation



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T O F l C ENZYMATIC METHOD OF MAKING PECTIC PREPARATION Herbert T. Leoand Clarence C. Taylor, Anaheim, Calif.

No Drawing. Application November 20, 1946, Serial No. 711,195

14 Claims. i

This invention relates generally to the enzymatic treatment of pectinfor preparing novel pectic substances, inter alia, those disclosed inour co-pending application Serial No. 616,654. filed September 15, 1945,now abandoned, entitled Novel Type of Pectic Substance and Method ofPreparing the Same, and therein designated with the term pectinylicacids.

More particularly, this invention relates to the treatment of pectinwith the enzyme pectase.

By the term pectase we mean an enzymatic material derived from asuitable vegetable source and capable of acting on soluble pectin toconvert the same into a more or leSs incompletely demethoxylatedproduct, herein referred to as pectinic acids. Whether or not pectaseincludes only a single enzyme or a group of enzymes is not definitelyknown. For this reason, the term "pectase is used in this application tocover .both any single enzyme and any mixtures of enzymes capable ofacting on soluble pectin with the above-mentioned results. We do notinclude within the scope of this term other pectic enzymes such aspectinase which is said to efiect a complete decomposition of the pectinmolecule into its various single component parts.

The starting material in the process disclosed in our said co-pendingapplicationis an aqueous dispersion of pectin, preferably a pectinextract of fruit or other vegetable material obtained by the action ofan acid aqueous medium on said fruit or other vegetable materialfollowed by a separation of residual fruit pulp from the extract, as byfiltration with the use of a filter aid (diatomaceous earth). Mostsuitably, the filtered extract is concentrated by evaporation, say, toabout one-half or one-quarter of its original volume. According to themethod disclosed in our said co-pending application, we incorporate withsuch an aqueous pectin dispersion or extract calcium carbonate or thelike in an amount sufiicient to maintain the pH value in said dispersionor extract at at lea't 5.3. We also incorporate with the pectindispersion or extract a suitable amount of pectase and maintain theresulting mixture at a suitable temperature (below 160 F.) while pectaseaction is allowed to progress. The action of the pectase on the pectincauses the precipitation of a calcium-pectinic acid jelly soon afterpectase action has been initiated, and this jelly grows increasinglyfirm. When pectase action has progressed to any desired point, thepectase action is terminated, preferably by washing thecalcium-pectinylic acid jelly (which contains almost all of the water ofthe treated pectin dispersion or extract) with acidified aqueousalcohol. This washing also serves to dehydrate the jelly to aconsiderable extent and to remove a, major portion, if not all, of thecalcium present in said jelly, to yield a product that after drying andgrinding represents the final product.

It will be noted that the process disclosed in our said copendingapplication involves initially providing an aqueous dispersion of pectinand causing pectase to act on said aqueous dispersion with resultantprecipitation of a calcium-pectinic acid jelly which is subsequentlywashed with acidified aqueous alcohol.

We have now found that we can cause a pectase dispersion to act onpectin in solid form to produce the above-mentioned pectinylic acids andother desirable pectin materials. Mor particularly, we have found thatan eminently suitable starting material for the modification of pectinby means of pectase is to be found in a coprecipitate of aluminumhydroxide and pectin. Such a coprecipitate of aluminum hydroxide andpectin may be prepared by precipitating aluminum hydroxide in a pectindispersion or a pectin extract, for instance, (in the manner disclosedin our copending application Serial No. 687,956, filed August 2, 1946,now U. S. Patent No. 2,425,947, issued August 19, 1947, entitled Methodof Preparing Pectin. By such pectase treatment of solid pectin, inparticular, a coprecipitate of aluminum hydroxide and pectin, we canprepare the very same products as those obtained by the method disclosedin our copending application Serial No. 616,654. As described in theaforementioned Patent No. 2,425,947, pectin and aluminum hydroxide maybe coprecipitated' by treating a dilute aqueous solution of pectin withcalcium carbonate to effect a pH of from 6.00 to 6.80 after the removalof liberated carbon dioxide, and adding to the extract an aqueoussolution of a water soluble aluminum compound, such as aluminumchloride, to effect a pH of 3.70 to 4.50 in the mixture. The resultinggelatinous pectin-aluminum hydroxide coprecipitate may then be filtered,washed with acidified alcohol, and dried.

When solid pectin is treated with pectase according to our presentinvention, the pectin remain in solid form. No jelly is formed, and allthe difliculties inherent in handling a jelly are avoided. Further, thetreatment of solid pectin with pectase makes possible considerableeconomies. Thus, it is possible-to treat an aluminum hydroxide-pectincoprecipitate containing very little water, as compared with the pectindispersion or extract in which such a coprecipitate is formed. It shouldbe remembered that practically all pectin is obtained by a processincluding an initial extraction of fruit or vegetable material and thatcoprecipitation with aluminum hydroxide probably represents the cheapestmethod of concentrating the pectin content of the resulting extract. Bytreating a coprecipitate of aluminum l:ydroxide and pectin with pectase,we avoid the necessity for removing water either by concentrating apectin extract or by alcohol washing of the jelly obtained by a pectasetreatment either of the original extract or a concentrate thereof.

It should further be noted that treatment of solid pectin, inparticular, of a coprecipitate of pectin and aluminum hydroxide,involves the treatment of pectin in more concentrated form than thetreatment of an aqueouspectin dispersion or extract or concentratethereof. Hence, treatment of solid pectin with pectase according to thepresent invention can be carried out in tanks or other equipment of muchsmaller volumetric capacity than the apparatus required for treatmentwith pectase of pectin dispersions. ,Finally, it should be noted thattreatment with pectase of pectin according to the present inventioninvolves a minimum of departure from standard methods of producingpectin involving, in sequence, the steps of extracting pectin fromvegetable or fruit material, filtering the resulting extract,coprecipitating aluminum hydroxide and pectin from the filtered extract,washing out aluminum from the coprecipitate with acidified aqueousalcohol, drying and grinding. To prepare modified pectic substancesaccording to the present invention, it is only necessary to insert apectase treatment following the coprecipitation of aluminum hydroxideand pectin and immediately before the washing with acidified aqueousalcohol. No apparatus of special design is required, as when handlingthe jellies obtained when proceeding, according to the methods of ourapplication Serial No. 616,654.

It is therefore an important object of the present invention to providean improved and relatively inexpensive method of treating pectin withpectase comprising the step of causing said pectase to act on solidpectin, preferably a coprecipitate of pectin and aluminum hydroxide thatis wetted with water or that contains absorbed water.

Other and further objects and features of the present invention willbecome apparent from the following description and appended claims.

In proceeding according to the present invention, we use as a preferredstarting material a coprecipitate of aluminum hydroxide and pectin suchas may be prepared from a pectin ex-. tract of fruit or vegetablematerial by methods well known in the art. The coprecipitate may beformed by the method disclosed in our application Serial No. 687,956. Asdescribed in the previously mentioned application Serial No. 687,956,pectin and aluminum hydroxide may be coprecipitated by treating a diluteaqueous solution of pectin with calcium carbonate to effect a pH from6.00 to 6.80 after the removal of liberated carbon dioxide, and addingto the extract an aqueous solution of a water soluble aluminum compound,such as aluminum chloride, to effect a pH from 3.70 to 4.50 in themixture. The resulting gelatinous pectinaluminum hydroxide coprecipitatemay then be filtered, washed with acidified alcohol, and dried. Weprefer to filter ofl this coprecipitate from the extract in which it wasformed and to compress the coprecipitate, as by means of a screw presssuch as the Leo press or by means of a filter press. Thepress cakes thusobtained are preferably shredded or disintegrated and screened, forinstance, through a fouror eight-mesh screen. The resulting granularproduct contains absorbed water, but feels relatively dry to the touchand is capable of absorbing relatively large additional amounts of waterwhile retaining its granular form. One pound of the screened, shreddedaluminum hydroxide-pectin coprecipitate fills almost exactly a quartcontainer (after tamping). To one pound of the pressed, shredded, siftedcoprecipitate we can add 500 cc. of water without increasing the volumeof said one pound of coprecipitate and without the appearance ofpractically any free liquid.

Starting with such a relatively firm, shredded, sifted and absorbentcoprecipitate of aluminum hydroxide and pectin, we may add to each poundthereof, for instance, a mixture of 250 c. c. of pectase solution, 250c. c. of tap water, and 6 grams of chalk. The enzyme solution, water,and chalk are mixed together, and the resulting mixture is quicklystirred into the coprecipitate. It is important to mix the enzyme,water, and chalk before adding the resulting mixture to thecoprecipitate, because the pressedout coprecipitate will absorb theliquid quickly and the pectase action is quite rapid. If thepectasefwater, and chalk were stirred into the coprecipitate separately,a homogeneous mixture may not be obtained at once, and the pectaseaction may not be uniform throughout the coprecipitate.

The above-disclosed amounts of enzyme solution, water, and chalk aregiven by way of example only. The exact amount of enzyme to be addeddepends upon the potency of the enzyme infusion or solution beingincorporated and upon the desired rate of pectase action. The amount ofwater added is a function of the volume of pectase solution added, for,ordinarily,

we prefer, in effect, to dilute the enzyme solution with the added waterto the point where the resulting diluted pectase solution, while asdilute as possible, still will be completely absorbed by thecoprecipitate. By the use of a pectase solution of maximum dilution wesecure a more uniform pectase action. The amount of chalk or other addedneutralizing agent (selected from the alkaline earth metal salts and themagnesium compounds) is that required to maintain a pH of at least 5.3and preferably between 5.8 and 6.0 throughout the pectase action.

The pectase action is allowed to proceed at a suitable temperature below160 F., for instance, between and F. As pectase action progresses, someliquid is squeezed out from the coprecipitate.

When pectase action has progressed to any desired point, the pectaseaction is terminated, preferably by adding to the reaction mixtureenough alcohol (ethyl alcohol, isopropyl alcohol, or the like) to form amixture containing about 40% alcohol. This addition of alcohol not onlyterminates the enzyme action but also dissolves out any material solublein aqueous alcohol that might tend to interfere with subsequentextraction with acidified aqueous alcohol. The free aqueous alcohol isnext drained off, as through a reel. To the drained-oft solid materialwe add sumcient alcohol to form a mixture containing preferably between50 and 60% alcohol. To the resultant mixture we add sumcient acidifiedaqueous alcohol of the same concentration to bring down the pH of themixture to about 1.00. The preferred acid employed is hydrochloric acid.By adding the acid mixed with alcohol to the pectic material admixedwith alcohol, we avoid any dissolution of pectic material withconsequent formation of slimy matter and incomplete washing out ofimpurities, calcium and aluminum compounds and the like. Ordinarly 50 c.c. of concentrated hydrochloric acid is sufficient to establish a pH of1.00 in a mixture containing one pound of coprecipitate. After thecoprecipitate has been allowed to soak in the acidified aqueous alcoholfor some time, the acidified aqueous alcohol is drained off. The washingwith acidified aqueous alcohol is then repeated, using preferably foreach pound of coprecipitate 8 fluid ounces of 80% alcohol and 10 c. c.of concentrated hydrochloric acid to maintain a pH of about 1.00. Aftera brief soakin this acidified aqueous alcohol is drained off, and thesolid pectic material is thereafter washed repeatedly with 'highstrength (about 80%) alcohol until a pH of from 2.3 to 2.5 is reached.At that time the pectic material is washed with high strength alcoholcontaining sufficient sodium lactate to raise the pH to 3.0 or higher.After this washing with alcohol containing sodium lactate, the pecticmaterial is ready to be pressed, vacuum-dried, and pulverized to yield awater soluble product suitable for the preparation of jellies.

The progress of the pectase action may be followed by measuring, fromtime to time, the minimum pH required for dissolution of thecalcium-pectinic acid combination present in the reacting mixture or bymeasuring the minimum pH required for formation of a calciumpectinicacid jelly from the pectic material present in the reacting mixture.Methods for determining the minimum pH required for dissolution of thecalcium combination and for determining the minimum pH required forformation of a calcium jelly are disclosed in our said copendingapplication Serial No. 616,654, and also in our co-pending applicationSerial No. 631.487, filed November 28, 1945, entitled Method of TestingPectic Substances."

A preferred method for following the progress of the pectase action isdescribed as follows. A 50% lactic acid solution having a pH of about0.60 is prepared. We also prepare a 12 solution of hydrochloric acidhaving a'pH of about 0.10. The pH required for di solution of acombination of calcium with pectase treated pectin is determined byusing these two acid solutions. For this purpose, samples of thepectinaluminum hydroxide coprecipitate being treated with pectase aretaken from time to time during the pectase action (suitably at 5 tominute intervals). More particularly, a 100 cc. beaker is packed withthe wet coprecipitate. The coprecipitate thus measured out istransferred into a 250 cc. beaker. During the first stages of thepectase action, we add to the coprecipitate in the 250 cc. beaker, 30cc. of the 50% lactic acid solution, to form a mixture having a pH ofabout 2.00. When this test is carried out before the pectase di persionhas been incorporated with the coprecipitate, the coprecipitate willdissolve quickly to form a smooth pa te. When samples are takenthroughout the first stages of the pectase action, it will be noted thatthe coprecipitate in successive samples will dissolve pro gressivelymore slowly until, at said pH oi 2.00, the treated pectin simply swellsand does not so into solution. This end point is very easily recognized,for the swollen but undissolved particles of treated pectin (which maybe held together by water containing a minute quantity of dissolvedpectin) present a characteristic appearance similar to tapioca paste.This end point has been chosen as suitable in the preparation of pectasetreated pectin particularly adapted for making jellies containing morethan sugar.

If it is desired to prepare a more calcium susceptible pectase treatedpectin, for instance, a pectase treated pectin suitable for thepreparation of custard-like milk jellies, then the pectase treatment iscarried past the above disclosed end point. Past this end point, weemploy the above described 12 /2% hydrochloric acid solution. As whenusing the lactic acid, we continue to take samples at from 5 to 10minute intervals, measure out the amount of coprecipitate disclosedhereinabove, and add 30 cc. of hydrochloric acid to form a mixturehaving a pH of 0.60. Pectase treatment is allowed to progress until, bythe use of the hydrochloric acid solution to efiect a pH of 0.60, weagain reach an end point where the treated coprecipitate particles onlyswell but do not go into solution. The pectase treatment is thenterminated by methods disclosed hereinabove.

The above described tests can be carried out within less than 3 minutes.There is a remarkable difference in appearance between the variousacid-coprecipitate mixtures obtained from five samples taken within 30minutes. The accuracy of our method of testing has been verified byisolating and characterizing the pectase treated pectin obtained whenusing our method of testing. For instance, in 10 separate successivetreatments of pectin with pectase according to the presently describedmethod, and terminating the pectase treatment of the first of the twoabove disclosed end points (employing lactic acid) we prepared tenpectinic acid batches characterized by setting times (in the preparationof 65% sugar jellies) that did not vary from each other by more than 2minutes.

If it is desired to terminate the pecta e action at other stages thanthose represented by the above disclosed two end points, then the sametest can be carried out using different amounts of acids to effect otherpH values, for the pH at which transition from dissolution to swellingof the treated coprecipitate occurs is a definite characteristic of eachstage in the progressive pectase action. Thus, the tests may be carriedout by preparing an acid-coprecipitate sample mixture having a pH valueof, for instance, 1.50 or 1.00, to prepare pectase treated pectinscharacterized by definite and characteristic jellying properties, inparticular, setting times and calcium susceptibilities.

ods of the present invention are applicable for 7 effecting a pectaseaction of an aluminum hydroxide-pectin coprecipitate at any state of itshandling, from the moment when it has been precipitated to the time whenit has been removed from the filter press. Thus, after such acomecipitate has been formed, it is quite feasible to drain off some orall of the liquid in which the coprecipitate was formed (if thecoprecipitate tends to float on top of the liquid) or to drain onsupernatant liquid (in the event the coprecipitate tends to settle tothe bottom), and then incorporate chalk and pectase with the wetcoprecipitate. Pectase action will then proceed as disclosedhereinabove, and when the pectase ac- To illustrate more clearly theworking of the present invention, specific examples of methods accordingto the present invention are disclosed hereinbelow.

To each of two 1 lb. sampes of shredded and sifted pectin-aluminumhydroxide coprecipitate prepared from orange according to the methods ofour said co-pending application Serial No. 687,956, we added 250 cc. ofa solution of lemon pectase diluted with 250 cc. of tap water and having6 grams of chalk dispersed therein. The

No.11 20. c. 3c.c. 40.0.

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No.11 2c.c 3c.c 4c.c

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No. [II 2 c. c 3 o. o. 4 c. c.

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exture Finn Firm Finn.

We noted that samples I and II were much slower setting than samplenumber HI- and yielded jellies slightly firmer than the Jellyobtemperature during pectase action was 98 F.

The first sample was treated for 15 minutes, while the second sample wastreated for 30 minutes. In the case of both samples, pectase action wasterminated by addition of alcohol, and two rinsings with acidifiedaqueous alcohol were carried out at a pH of 1.0, the pectic product thenbeing washed with neutral highstrength alcohol and finally with alcoholcontaining sodium lactate to raise the pH to 3.0, all as disclosedhereinabove.

We also washed 9. 1 lb. sample of the same pectin-aluminum hydroxidecoprepicitate twice with acid alcohol (at 55% alcohol concentration anda pH of 1.0), finally washing with neutral high-strength alcohol andwith an alcoholic sodium lactate solution.

Hereinafter, the sample treated with pectase for 15 minutes isidentified as sample I; the sample treated with pectase for 30 minutesas sample II; and the untreated sample, as sample III.

The same yield of pectin was obtained in all three experiments, withinthe limits of experimental error.

65% sugar jellies were prepared from all three samples by a standardmethod. In each case, 500 grams sugar, 325 cc. distilled water, 2.25grams of pectic material (assumed to be 225 grade) and 2 cc. of a 25%sodium citrate solution were boiled to 65% sugar content. The syrup thusprepared from each sample was divided between three jelly glassescontaining, respectively, 2 cc., 3 cc., and 4 cc. of a 50% citric acidsolution. The Jelly glasses were allowed to stand, the time required forjelly formation was noted, and the jellies obtained were turned out fromthe jelly glasses for the purpose of checking the strength of the jellyand to determine the jelly grade of the pectin samples. The resultsobtained are tabulated as follows:

tained from number III. In other words, there was no loss in jellygrade. In this connection, it should be noted that when the setting timeof a pectin is increased by conventional means, as by treatment in acidalcohol at a pH of 1.0 for two and one-half hours, the production of apectin having a setting time of seven minutes involves a 10% loss injelly strength, without rendering the pectin at all susceptible toprecipitation by calcium.

We also prepared actual fruit jellies from said three samples by usingstandard commercial grape juice (Welch) and standard commercial cider(Martinelli). Standard grape juice has a pH of 3.40, which we lowered bythe addition of 15 cc. of 50% citric acid solution to 1 liter of grapejuice to form a jelly having a pH of 3.25. Standard commercial cider hasa pH of 3.75,

which we lowered by addition of 25 cc. of 50% The grape juice jelly wasprepared from 450 grams of sugar, 325 cc. of the grape juice containingadded citric acid, 2.25 grams of 225 grade pectic material, and 2 cc. ofa 25% sodium citrate solution.

The apple jelly was prepared from 475 grams sugar, 325 cc. cidercontaining added citric acid, 2.25 grams of 225 grade pectic material,and 2 cc. of 25% sodium citrate solution.

In each instance, the pectic material was dissolved in the Juicecontaining the citric acid and the sodium citrate, then adding the sugarand finally boiling the resulting mixture to a 65% sugar content. Theresulting syrup was then poured out into jelly glasses.

Samples I and II were characterized by a drastically reduced temperatureof set, as compared to sample III. The syrup cooled in the jelly glassesbefore a jelly was formed, at least 27 minutes being required for jellyformation. The jellies obtained from samples I and II were much firmerthan the jellies obtained from sample 111.

The difierence in calcium susceptibility between the three samples isindicated by the following data.

Of each sample, sufilcient pectic material to be equivalent to' 2 gramsof grade material were dissolved (by heating) in 100 c. c. of watercontaining 0.4 gram of sodium citrate. One tablespoon of vinegar wasadded to each solution.

No jelly formed in any of the solutions on cooling.

The same test was repeated, 0.08 gram 01 calcium lactate beingincorporated with the solutions of pectic material. In this case, thesolutions obtained from samples I and III remained fluid, but thesolution obtained from sample II formed a weak jelly.

The test was again repeated using twice the indicated amount of calciumlactate. The solution obtained from sample III remained fluid; thesolution obtained from sample I formed a. soft jelly; the solutionobtained from sample 11 formed a firm Jelly.

A custard-like milk jelly was prepared from sample 11 as follows; Amixture was made up of the pectic material of sample III, dextrose, andsodium citrate. The proportions of pectic material, dextrose, and sodiumcitrate were adjusted to yield a 100 grade material containing 20%sodium citrate and 4% calcium lactate. 3 ounces of 100 grade material soprepared were dissolved in 8 ounces tap water by boiling. The additionto the resulting solution of one cup milk or one fluid ounce can ofcondensed milk yielded an excellent custard-like milk jelly aftercooling in a refrigerator.

Proceeding on a larger scale, pectin may be treated with pectase asfollows. A pectase dispersion is first prepared from lemon or orangepeel. For this purpose, lemon or orange peel is ground with a smallamount of water. The mixture of water and peel thus obtained is bodilyremoved from the mill and sufiicient calcium carbonate is added, alongwith some sodium chloride, to raise the pH to between 6.0 and 7.0.Within a very short time the pectase will coagulate all the pecticsubstances in solution. It is then quite easy to press or filter out avery potent pectase dispersion. To 100 gallons of such a dispersionprepared from lemon peel we add lbs. of calcium carbonate to prepare apectase dispersion-calcium carbonate mixture sufllcient to treat 200gallons of pectin-aluminum hydroxide coprecipitate press cake to form infrom 1 to 2 hours a very calcium susceptible pectinic acid suitable forthe preparation of custard-like milk jellies. When orange peel isemployed. one part of the pectase dispersion obtained therefrom isdiluted with 2 parts of water, and 15 lbs. oi. calcium carbonate areadded to 100 gals. oi the diluted pectase dispersion, to yield a.pectase dispersion-calcium carbonate mixture likewise suitable for thetreatment of 200 gals. of pectinaluminum hydroxide coprecipitate presscake for the preparation within 1 to 2 hours of a very calciumsusceptible pectinic acid suitable for the preparation of custard-likemilk jellies.

It will thus be seen that we have provided a novel method of treatingpectin with pectase in which the pectin is maintained throughout saidtreatment in solid state at the pH of at least 5.3 by incorporationtherewith of a neutralizing composition selected from the groupconsisting of alkaline earth, metal salts and magnesium compounds. Thepreferred starting material is an aluminum hydroxide-pectincoprecipitate. Many details of procedure and composition may be variedwithin a wide range without departing from the principles of thisinvention, and it is therefore not our purpose to limit the patentgranted on this invention otherwise than necessitated by the scope ofthe appended claims.

Reference is made to our said co-pendlng an- I0 plications for featuresnot disclosed or discussed in the present application.

We claim as our invention:

1. The method of enzymatically treating pectin which comprises providinga moist relatively firm pectin-aluminum hydroxide coprecipitate capableof absorbing an additional amount or water incorporating with saidcoprecipitate a neutralizing agent selected from the group consisting ofalkaline earth metal salts and magnesium compounds in an amountsufiicient to maintain said coprecipitate at a pH of at least 5.3throughout said enzyme treatment, incorporating an aqueous pectasedispersion with said coprecipitate in an amount only suflicient forabsorption thereby, maintaining the resulting mixture at a temperatureat which the pectin will be chemically modified by said pectase,terminating the action 01 the pectase on said pectin. and washing saidcoprecipitate with acidified aqueous alcohol to remove aluminumhydroxide and calcium compounds from the resulting solid pectic product.

2. The method of enzymatically treating pectin which comprises providinga solid pectin containing material, maintaining said material in a moistyet solid condition at a pH of at least 5.3 but not substantially over6.0 by incorporating therewith a neutralizing substance selected fromthe group consisting of alkaline earth metal salts and magnesiumcompounds, incorporating pectase with said material, maintaining theresulting mixture in its solid form at a temperature at which the pectinwill be chemically modified by said pectase, terminating the action ofthe pectase on said pectin, and removing calcium containing materialfrom the resulting solid pectic product.

3. The method of enzymatically treating pectin which comprises providinga pectin-aluminum hydroxide coprecipitate in solid form but moistenedwith the aqueous medium in which said coprecipitate was precipitated,incorporating with said coprecipitate calcium carbonate in an amountsufllcient to maintain the pH of said coprecipitate at at least 5.3throughout said pectase action, incorporating pectase with saidcoprecipitate, maintaining the resulting mixture in its solid form at atemperature at which the pectin will be chemically modified by saidpectase, terminating the action of the pectase on said pectin, andwashing said coprecipitate with acidified aqueous alcohol to removealuminum hydroxide and calcium containing material from the solid pecticproduct resulting from said enzyme treatment.

4. The method of treating pectin with pectase which comprises providinga pectin-aluminum hydroxide coprecipitate in solid form but moistenedwith the aqueous medium in which said coprecipitate was precipitated,the amount of said aqueous medium being reduced to the point where saidcoprecipitate has a granular form and is capable of absorbing anadditional amount of water, providing an amount of a pectase dispersioncapable of being absorbed by said coprecipitate and having dispersedtherein calcium carbonate in an amount sufllcient to maintain saidcoprecipitate at a pH of at least 5.3 throughout said pectase treatment,incorporating said pectase disperson with said coprecipitate,maintaining the resulting granular mixture at a temperature at which thepectin will be chemically modified by said pectase, terminating theaction of the pectase on said pectin, and removing aluminum hydroxideand calcium containing material from the resulting pectic product, thepectin throughout the entire treatment remaining in solid form.

5. The method of treating pectin with pectase which comprises providinga pectin-aluminum hydroxide coprecipitate, incorporatingwith saidcoprecipitate calcium carbonate in an amount sufficient to maintainthroughout the pectase action the pH of said coprecipitate at at least5.3 but not over the pH normally brought about by the calcium carbonatepresent, incorporating pectase with said coprecipitate, maintaining theresulting mixture at a temperature at which the pectin will bechemically modified by said pectase, and, when the pectase action hasprogressed to any desired point, incorporating with said coprecipitatealcohol to form a mixture containing about 40% alcohol, draining on freealcohol from the resulting mixture, adding alcohol to the residual solidmaterial to form a mixture containing between 50 and 60% alcohol,incorporating with the resulting mixture alcohol of from 50 to 60%strength and containing acid in an amount sufilcient to reduce the pH ofthe resulting mixture to about 1.0, draining oil from the resultingmixture free acidified aqueous alcohol, washing the residual solidmaterial at a pH of about 1.0 with 80% alcohol, thereafter washingthesolid material with alcohol until a pH of from 2.3 to 2.5 is reached,thereafter washing the solid material with alcohol containing sodiumlactate until a pH of 3.0 is reached, and drying the solid product.

6. The method of enzymatically treating pectin which comprises providinga solid yet moist pectin-aluminum hydroxide coprecipitate, incorporatingwith said coprecipitate a neutralizing agent selected from the groupconsisting of alkaline earth metal salts and magnesium compounds in anamount suflicient to maintain said coprecipitate to a pH of at least 5.3but not substantially over 6.0 when said coprecipitate is subsequentlytreated with pectase, incorporating pectase with said coprecipitate,maintaining the resulting mixture at a temperature at which the pectinwill be chemically modified by said pectase, terminating the action ofthe pectase on said pectin when said coprecipitate no longer is solubleat a pH of about 2.0, and washing said coprecipitate with acidifiedaqueous alcohol to remove aluminum hydroxide and calcium compounds fromthe resulting pectic product, the pectin being in solid form throughoutthe entire treatment and said resulting pectic product being recoveredin solid form.

7. The method of enzymatically treating pectin which comprises providinga moist yet solid pectin-aluminum hydroxide coprecipitate, incorporatingwith said coprecipitate a neutralizing agent selected from the groupconsisting of alkaline earth metal salts and magnesium compounds in anamount sufficient to maintain said coprecipitate at a pH of at least 5.3but not substantially over 6.0 when said coprecipitate is subsequentlytreated with pectase, incorporating pectase with said coprecipitate,maintaining the resulting mixture in solid form at a temperature atwhich the pectin will be chemically modified by said pectase,terminating the action of the pectase on said pectin when saidcoprecipitate no longer is soluble at a pH of 0.60, washing saidcoprecipitate with acidified aqueous alcohol to remove aluminumhydroxide and calcium compounds from the resulting pectic product andrecovering such pectic product.

8. The method of enzymatically treating pectin 12 which comprisesproviding a water moistened solid coprecipitate of pectin and aluminumhydroxide, incorporating'calcium carbonate into said coprecipitate tomaintain the same at a pH numerically equal to at least 5.3,incorporating a water dispersion of pectase with said coprecipitate forabsorption thereby and admixture therewith while retaining the solidcharacter of said coprecipitate, maintaining the resulting mixture at atemperature at which said pectase chemically modifies said pectin,terminating the action of the pectase on said pectin and removingaluminum hydroxide from the resulting pectic product.

9. The method of enzymatically treating pectin, which comprises admixingwith a coprecipitate of pectin and aluminum hydroxide in solid granularform an aqueous dispersion of pectase containing a suflicient quantityof calcium carbonate to maintain the resulting admixture at a pHnumerically equal to at least 5.3 but not substantially over 6.0,maintaining said admixture while still in granular form at a suitabletemperature below F. at which said pectase will chemically modify saidpectin, terminating the action of the pectase on said pectin at thedesired point and washin said still solid admixture with acidifiedalcohol to remove aluminum and calcium compounds therefrom and recover asolid pectic product.

10. A process for preparing low-methoxyl pectinic acids from a diluteaqueous solution of pectin which comprises adding to said solution anacid reacting solution of an aluminum salt to adjust the pH of thesolution to about 4.2 to 4.5 to precipitate a water-insolublepectin-aluminum composition, separating the precipitated pectinaluminumcomposition and subjecting it to the action of an enzymicdemethoxylating agent to form low-methoxyl pectinic acids and thenisolating the low-methoxyl pectinic acids.

11. A process for preparing low-methoxyl pectinic acids from a diluteaqueous solution of pectin which comprises adjusting the pH of thesolution to about 3.70 to 4.50 in the presence of a dissolved aluminumsalt to precipitate a waterinsoluble pectin-aluminum composition,separating the precipitated pectin-aluminum composition, mixing waterwith said precipitate, subjecting the mixture to the action of anenzymic demethoxylating agent to form low-methoxyl pectinic acids andthen isolating the low-methoxyl pectinic acids.

12. A process for preparing low-methoxyl pectinic acids from a diluteaqueous solution of pectin which comprises adjusting the pH of thesolution to about 3.70 to 4.50 in the presence of a sumcient quantity ofa dissolved aluminum salt to precipitate a water-insolublepectin-aluminum composition, separating the precipitated pectinaluminumcomposition, adding water to said precipitate, subjecting the resultingmixture to enzymic demethoxylation at a pH of at least 5.3 in thepresence of pectase, and then isolating the low-methoxyl pectinic acidsso formed.

13. A process for preparing low-methoxyl pectinic acids from a diluteaqueous solution of pectin which comprises adjusting th pH of thesolution to about 3.70 to 4.50 in the presence of a sufiicient quantityof a dissolved aluminum salt to precipitate a water-insolublepectin-aluminum composition, separating the precipitated pectinaluminumcomposition, adding water to said precipitate, subjecting the mixture todemethoxylation in the presence of pectase at a pH of at leastREFERENCES crrnn The following references are of record in the fileofthis patent:

UNITED STATES PATENTS Number Name Date 1,405,055 McDermott et a1. Jan.31, 1922 1,497,884 Jameson et a1 June 17, 1924 1,51,615 Leo Oct. 28,1924 1,908,225 Currie et a1 May 9, 933 2,115,479 Beach Apr. 26, 19382,358,430 Willaman et a1. Sept. 19, 944 2,444,266, Owens et a1 June 29,1948

1. THE METHOD OF ENZYMATICALLY TREATING PECTIN WHICH COMPRISES PROVIDINGA MOIST RELATIVELY FIRM PECTIN-ALUMINUM HYDROXIDE COPRECIPITATE CAPABLEOF ABSORBING AN ADDITIONAL AMOUNT OF WATER, INCORPORATING WITH SAIDCOPRECIPITATE A NEUTRALIZING AGENT SELECTED FROM THE GROUP CONSISTING OFALKALINE EARTH METAL SALTS AND MAGNESIUM COMPOUNDS IN AN AMOUNTSUFFICIENT TO MAINTAIN SAID COPRECIPITATE AT A PH OF AT LEAST 5.3THROUGHOUT SAID ENZYME TREATMENT, INCORPORATING AN AQUEOUS PECTASEDISPERSION WITH SAID COPRECIPITATE IN AN AMOUNT ONLY SUFFICIENT FORABSORPTION THEREBY, MAINTAINING THE RESULTING MIXTURE AT A TEMPERATUREAT WHICH THE PECTIN WILL BE CHEMICALLY MODIFIED BY SAID PECTASE,TERMINATING THE ACTION OF THE PECTASE ON SAID PECTIN, AND WASHING SAIDCOPRECIPITATE WITH ACIDIFIED AQUEOUS ALCOHOL TO REMOVE ALUMINUMHYDROXIDE AND CALCIUM COMPOUNDS FROM THE RESULTING SOLID PECTIC PRODUCT.